Chucking and driving device



April 30, 1946. w. J. NIGHTINGALE CHUCKING AND DRIVING DEVICE Filed001:. 25, 1944 5 Sheets-Sheet 1 as N JyM

April 30,1946. w. J. NIGHTINGALE I 2,399,290

CHUCKING AND DRIVING DEVICE Filed Oct. 25,-1944 5 Sheets-Sheet 5 April30, 1946. w. J. NIGHTINGALE 2,399,290

CHUCKING AND DRIVING DEVICE Filed Oct. 25, 1944 '5 Sheets-Sheet 4 W. J.NIGHTINGALE CHUGKING AND DRIVING DEVICE April 30, 1946.

Filed on. 25; 1944 5 Sheets-Sheet 5 Patented Apr. 30, 1946 cnucmne ANDDRIVING DEVICE William J. Nightingale, Oak Park, Ill., assig'nor ofone-half to George C. Bruen Application October 25, 1944, Serial No.560,261

19 Claims.

This invention relates to a chucking and driving device, and moreparticularly to a device adapted for attachment to the live spindle of alathe.

"The devices disclosed and claimed here comprise improvements of devicesof the kind shown and claimed in my copending application Serial No.495,141, filed July 17, 1943, entitled Universal multi-dogging device,now Patent No. 2,367,045, granted January 9, 1945.

One of the features of this invention is that it provides an improveddriving or dogging device for use on a lathe; another feature of thisinvention is that a single unit of the character disclosed here may beused throughout a range of work piece sizes that heretofore has requiredthe use of a multiplicity of dogs of the prior conventional type; stillanother feature of this invention is that the work piece may be veryquickly and accurately clamped in position in proper relation to thecenter point element of the driving spindle of a lathe; yet anotherfeature of this invention is that the device is so constructed andarranged as to compensate for any slight misalignment between the axisof the work piece and the axis of the center point element; a furtherfeature of this invention is the provision of spring means biasing themovable mounting member of the device to a desired normal position inperfect alignment with the axis of the center point element; yet afurther feature of this invention is that the work may be held tightlyagainst the center point element without the use of a bridle or strap;and still a further feature of this invention is that the device isoperated as a two jaw chuck when desired. Other features and advam tagesof this invention will be apparent from the following specification andthe drawings, in which:

Figure 1 is a front elevational View of a preferred form of deviceembodying my invention; Figure 2 is a side elevational view of thedevice shown in Figure 1 with part of the cylindrical guard housingbroken away; Figure 3 is a vertical sectional view along the line 33 ofFigure 2; Figure 4 is a vertical sectional view at right angles to thatof Figure 3, along the line 44 of Figure 1;

Figure 5 is a top plan view of the device with the housing partly brokenaway; Figure 6 is a partial vertical sectional view along the line 6-8of Figure 4; Figure '7 is a fragmentary horizontal sectional view alongthe line ll of Figure 6; Figure 8 is a fragmentary detail sectional viewalong the line 8-8 of Figure 3; Figure .9 is a front elevational view ofanother form of device embodying my invention; Figure 10 is a verticalsectional view of this device along the line Ill-10 of Figure 9; Figure11 is a top plan view of the device shown in Figure 9 with part of thehousing broken away; Figure 12 is a partial vertical sectional viewalong the line 12-42 of Figure 10; Figure 18 is a horizontal sectionalview along the line I3l3 of Figure 10; Figure 14 is a fragmentary detailsectional view along the line I4l4 of Figure 10; Figure 15 is a detailplan view of another form of connection for one end of the mountingmember of the device shown in Figure 9; and Figure 16 is a fragmentarysectional view along the line Iii-I 6 of Figure 15.

The majority of work on a lathe is done with the work piece supportedbetween the live or head stock and the tail stock. There are manysituations, however, where the work cannot be done with the tail stockin place. Under these circumstances some holding and driving connectionmust be made between the work piece and the driving spindle, the otherend of the work piece usually being supported in a steady rest. Theabovementioned connection has heretofore been commonly provided by theuse of a dog, the dog having an open body portion within which the workpiece is received and clamped, and an L- shaped tail adapted to bereceived in a radial slot in a face plate which must be attached to thedriving spindle. In some cases a straight tailed dog is used inconnection with a face plate having a driving stud. In either case, itis necessary to have a plurality of dogs and to use different dogs ofthe set for work pieces of diflerent size, each dog being capable of usethrough only a very small range of work piece size. Further, thisarrangement has an off-center or unbalanced effect which is hard on thelathe and which sometimes results in vibration of the work piece.Furthermore, particularly where the dog has an L-shaped tail, there is abending torque, exerted through a leverage effect on the work piece,which sometimes results in appreciable bending or bowing of theworkpiece particularly in smallersize rods or tubes an inch and a halfor less in diameter. The use of a dog also requires some kind of holdingmeans to keep the work piece pulled up tight against the center pointelement, a bridle or strap generally being used, This is awkward,frequently loosens up, and sometimes breaks.

Chucking and driving devices embodying my invention are capable ofhandling a very Wide range of sizes or work piece, can be leftpractically permanently on the driving spindle, and ensure perfectholding and clamping of the work piece without any undesired bending orother strains on the work piece. Furthermore, while the device includesmeans permitting desired movements of various kinds between certainparts, the driving connection is at all times positive and direct,without any play enabling vibration of the work piece during its drivingrotation.

Referring now more particularly to the specific embodiment of myinvention illustrated in Figures 1-8, the device is shown in position onthe head of a lathe having a live or driving spindle In including athreaded hub portion llla and a center point element lllb. Threaded onto the hub lOa is one portion Ila of a supporting member identified ingeneral at ll, the connection being screwed up tight to provide a rigidmounting rotatable with the driving spindle. The other portion I lb ofthe supporting member is mounted on the portion lla for rotational andaxial movement with respect thereto, what is here being termed axialbeing movement parallel to the axis of the spindle or center pointelement rotation. Referring now more particularly to Figures 4, 6 and'7, it will be seen that pins lZa and l2b are fixedly mounted inopposite sides of the supporting member portion Ila and are receivedwithin angularly disposed slots Nb and H1) in the outer supportingmember llb. Because of the angular disposition of the slots, as is bestseen in Figure 7, rotation of the portion l lb with respect to theportion lla eifects axial movement of the portion l lb. As will be morefull apparent later, this axial movement is of considerable advantage inpulling a work piece up against the center point element H31) andkeeping it snugly thereagainst during operation of the lathe.

The outer supporting member portion llb carries rigidly mounted thereonone element, here the socket element, of a universal or ball and socketjoint. The socket element is here shown as comprising two annular piecesl3 and l4 having their inner surfaces ground or otherwise shaped toprovide a concave band which is an annular portion of a sphericalsurface. The other or ball element of the joint, here identified a l5,has a convex partial spherical surface adapted to be received within andcooperate with the concave surface, the parts l3, l4 and I5 comprising ajoint capable of at least limited universal movement,

the ball part l5 carrying a mounting member and clamping laws to behereafter described. The joint portion of the device has been described,merely as a matter of convenience, as though it were an independent anddistinct portion of the device; but it would be understood that, for alloperative purposes, the socket element of the joint is part of thesupporting member and the ball part of the joint is part of the mountingclamping means carried by the supporting member. As may be best seen inFigure l, the annular part I3 is provided with a plurality of outwardlyextending radial arms here identified as l3a d, the outer ends of thesearms serving as the supporting means for a cylindrical housing or guardmember l6 enclosing the mounting and clamping parts of the device.

Inasmuch as driving or rotating force delivered from the spindle to theouter or socket portion of the joint must be transmitted to the inner orball portion l5 of the joint, drive connection means is provided whichprevents circumferential movement between these parts but permits anyother desired movement therebetween, at least through the limited rangenecessary for proper operation of this device. Referring moreparticularly to Figures 6 and 8, it will be seen that a drive pin H isjournalled in the outer socket portion of the joint comprising the partsl3 and M, and has its head rigidly connected to a slide block l8slidable in a slot IS in the ball element. This slot extends axially,and since the block I8 is a tight, although sliding, fit therein,circumferential movement between the joint parts is prevented and thereis a positive driving connection between these parts with no play orlost motion. The term circumferential movement is here being used inconnection with rotative movement about a center concentric with theaxis of rotation of the spindle and center point element of the lathe.This driving connection between the parts is such' however, that theball part may twist in its socket in any combination of movements abouttwo axes perpendicular to each other and t the axis of rotation of thespindle, one of these axes of movement of the joint parts coincidingwith the axis of the drive pin IT. Th result of this construc tion isthat the ball part may move sufiiciently to compensate for any slightangular misalignment between the axis of the work piece and the axis ofrotation of the spindle, and this compensating movement may take placeconstantly during driving operation without in any way impairing thepositive driving connection.

The ball element l5 carries a mounting member here identified in generalas 20. As ma be best seen in Figure 1, this mounting member 20 has amain transverse body portion operating as a slide and serving as meansfor carrying the clamping jaw H and 22, these latter being slidablymovable toward and away from each other in a radial direction, speakingwith respect to the axis of rotation of the spindle. Plate members orbacking means 2 la and 22a are fixedly mounted in the member 20 and havestuds 2lb and 22b rotatably mounted therein in such a manner as to beprevented from axial movement. The thread portions of the studs arethreaded into cooperating openings in the clamping members 2! and 22, sothat the studs comprise means for moving the body members into clampingengagement with a work piece 23. Openings lfia and I6!) in the guardhousing provide access to the studs TH?) and 22?).

As may be best seen in Figure l, the mounting member 2!] is connected tothe ball element IS in such a manner that it is slidably movable withrespect thereto. This connection is effected by a bolt 24 snuglyreceived within a vertical slot in the member l5, so that any movementof the member 20 with respect to the ball element I5 is vertical asviewed in Fig. 4, the bolt moving in the slot, or due to the over-sizedopening I 5a such movement may be a swinging movement about bolt 24 as acenter. In order to complete the connection another bolt 25 is provided,this bolt being snugly received in an appropriate opening in themounting member 20, but being received in an over-size opening l5a inthe ball element, so that movement between the parts is permitted. Thisconstruction prevents circumferential movement between the mountingmember 28 and the ball element l5, but permits other movement in a planetransverse to the axis of the spindle. As will be readily apparent, thisconstruction, by virtue of the ball and socket joint, automaticallycompensates for any angular misalignment be tween the axis of the workpiece 23 and that of the spindle l5; and the movement of the mountingmember 20 with respect to the ball part l5, in a plane transverse to theaxis of the spindle, automatically compensates for any lateralmisalignment of the work piece and spindle, or for unequal tightening ofthe jaws 2| and 22. The result is that the two clamping jaws shown canbe drawn up on the bar or tube comprising the work piece, the work pieceproperly and accurately positioned with respect to the center pointelement "lb, and any slight misalignment present, particularly when asteady rest is being used, being automatically compensated for withoutstrain on the work piece by the movements permitted in the drivingdevice during its driving operation. The angle of the slots IIb' and Nb"are such that driving rotation of the spindle, working against theresistance of the work piece to .rotation, tends to cause the outermounting member portion Hb to move back toward the lathe head, thisaction automatically keeping the work piece snugly against the centerpoint element lilb. When the lathe is stopped and it is desired to movethe work piece either toward or away from the center point element Illb,however, this is very easily accomplished manually by merely graspingthe cylindrical housing member l6 and rotating it a little in onedirection or the other while keeping the spindle stationary.

In order to initially maintain the mounting member and clamping parts ina normal desired position during setup and the like, I provide springmeans biasing these parts to desired position exactly transverse to andcentered with respect to the axis of rotation of the spindle l0. As maybe best seen in Figures 1 and 5, the mounting member 20 is provided withsidewardly extending (speaking with respect to the position of the partsas shown in Figure 1) arm portions 20a and 26b, these terminating inball parts 20a and 20b. Cooperating with each of these ball parts is apair of spring assemblies here identified in general as 21 and 28. Whilethese spring assemblies may for convenience be stamped out of only oneor two pieces of spring metal, they are for all operative purposescomposed of three leaf springs, which may be identified as 2|ac on theone hand and 28a--c onthe other hand. The pair of opposed spring pieces21a and 210 on the one hand, and 28a and 280 on the other hand,cooperate with ball parts normally to urge the mounting member andthe-parts carried thereby to the desired normal position, being assistedin this by the opposing action of the springs 21?) and 28b tending tocenter these parts laterally. This spring means or spring arrangementfor biasing the parts to a desired'normal position is highly importantin practice, since it assists in accurately centering and properlyclamping the work piece without undue time or difficulty in the setupoperation. For some purposes, particularly where the device is to beused as a two jaw chuck, I find it desirable to be able to lock-themounting member and parts carried thereby in rigid relation to thesupporting member. To accomplish this I provide the mounting member (or,speaking more precisely, the joint part it) with bosses [4a and I 4b. Inregistry with these bossesI provide lugs 20c and "26d through which Ipass studs 29 and 30 with pointed ends adapted to be received in conicaldepressions in the bosses I la and 14b when the studs are screwed in, asshown in the drawings.

This makes the whole assembly rigid and provides a very efiicient twojaw chuck. It will be understood, of course, that these studs are backedout I to permit the desired freedom of movement betweenthe parts whenthe device is merely acting piece is engaged by the tail stock or by asteady rest.

Referring now more particularly to the embodiment of my inventionillustrated in Figures 9,-14, it will be seen that this form of myinvention has some features similar to those of the dogging devicesshown in my above-mentioned copending application Serial No. 495,141,although in many respects this device corresponds to the device earlierdescribed. In so far as possible, therefore, parts of this form whichcorrespond with parts of the device shown in Figures 1-8 will be markedwith analogous reference numerals difiering by thirty from those used inthe earlier figures, so that the description can be shortened.

In this form of the device the threaded hub 40a of the spindle carries asupporting member 4! which in turn carries a mounting member 50 on whichare movably mounted clamping laws 5! and 52. The supporting member alsocarries a cylindrical housing member 46. In this form of my inventionthe supporting member is a single piece, the desired axial movement ofthe mounting and clamping members being efiected by the use of pins 6|and 62 axially movable in appropriate openings in the supporting memberM. The ends of the pins 6| and 62 are engaged by a cam ring 63 rotatablymounted on a supporting member 4|. As may be best seen in Figure 13, thecam ring has a pair of depressed portions,

as the portion 63a, which enable the pins to lie in the position shownin the drawings when these depressed portionsv register with the pins.When the cam ring is rotated by a hand rod, however, thepins may bepushed to the right (speaking with respect to the position of the partsas illustrated in Figure 10) to force the mounting and clamping membersto the right. This movement is permitted by virtue of the fact that themounting member is connected to the supporting member by mounting pinmembers here identified as 64 and, the cylindrical shank portions ofthese members being axially slidable in the openings in the supportingmember 4| receiving them. The mounting pin members and mounting andclamping members are normally urged axially in a direction toward thehead stock by springs 66 and 61 operative on the pins and .thesupporting member. When the cam ring 63 is in the position shown in thedrawings the mounting and clamping members are urged toward the spindleby the springs 66 and 61, thus holding the work piece. against thecenter point element, not shown in thes drawings. When it is desired toinsert a work piece, the cam ring would first be rotated to iorceablymove the mounting pin members, mounting member and clamping members tothe right, and then the laws or clamping members of the device would bepulled into engagement with the work piece. In setting up after the workpiece is properly clamped in the device, the cam ring would be turned tothe position shown in the drawings and the springs 66 and 61 would thenkeep the workpiece against the center point element. In this respect thedevice shown here is similar to that more fully described and claimed inmy above-mentioned copending application Serial No. 495,141.

The transverse mounting member is again provided with sidewardlyextending arm portions analogous to those shown in the device firstdescribed here, these being identified as 50a and 50b and terminating inball parts 50a and 50b. These ball parts again cooperate with two springassemblies rigidly mounted on the supporting member, these springassemblies being here shown as comprising the three leaf spring parts'5la--c on the one hand and 58ac on the other hand. This arrangementagain provides means biasing the mounting and clamping parts to adesired normal center position with respect to the spindle, althoughthey have sufiicient yield to permit desired movement during operationwithout stress on the work piece. When it is desired to lock the devicerigidly, studs 59 and 60 in lugs 50c and 50d may be screwed in to bearagainst bosses on the supporting member 4|.

The mounting of the mounting member 50 in the mounting pin members 64and 65 is in general analogous to the mounting arrangement shown in myaforementioned copending application Serial No. 495,141, and it willtherefore not be described in undue detail. The top and bottom portionsof the mounting member 50 (speaking with respect to the position of theparts as shown in Figure are formed into trunnion portions hereidentified as 506 and 50 As may be best seen in Figures 10 and 11, theupper trunnion portion is journalled in a mounting block '10 which isspring supported for limited movement in any direction in the mountingpin member 64. As may be best seen in Figure 14, the lower trunnion endportion 50 is journalled in a mounting block H which is axially slidablein the frame portion of the mounting pin member 65. It will be apparentthat there can be no circumferential movement between the lower end ofthe mounting member and the supporting member, so that when the workpiece is drawn up tight against the center point element there is apositive drive arrangement with no circumferential play. On the otherhand, in setting up the work piece, the full freedom of movement(through a limited range) provided the upper end of the mounting memberenables proper centering of the work piece on the center point elementof the spindle. In and out movement of both of the ends of the mountingmember, combined with the fact that the member can rotate about an axisthrough its trunnion end portions, enables it to compensate for angularmisalignment between the axis of the work piece and the axis of rotationof the spindle; and the lateral movement permitted by the mounting ofthe upper end and mounting block HI, coupled with the fact that themounting member can move vertically by sliding of the trunnions in theirmounting blocks 10 and H, enables compensation for any lateral orvertical displacement of the axis.

Referring now more particularly to Figures and 16, I show an improvedmounting arrangement for the end of the mounting member which is to havelimited movement in several directions in the mounting pin membersupporting it. In this case the trunnion end portion Me of the mountingmember is slidably and rotatably journailed in a bearing member 8! heldwithin an annular sleeve 82 of resilient material, as rubber, thissleeve in turn being mounted in the mounting pin member 94. Thisprovides a very simple and tight arrangement which nevertheless permitsthe desired axial or lateral movement of this end of the trunnion withrespect to the mounting pin member carrying it. This has veryconsiderable advantages, both in initial assembly and in freedom frombreakage or other trouble, and

comprises an improvement over the arrangement shown in the deviceillustrated more fully in Figures 9-14.

While I have shown and described certain embodiments of my invention, itis to be understood that it is capable of many modifications. Changes,therefore, in the construction and arrangement may be made withoutdeparting from the spirit and scope of the invention as disclosed in theappended claims.

I claim:

1. A driving device adapted to be attached to a rotating member having acenter point element and to clamp a piece of work in proper relation tosaid element, including: a supporting member adapted to be rigidlyattached to said rotating member; a mounting member mounted on saidsupporting member in such manner that cir cumferential movement isprevented but other movement with respect to the supporting member ispermitted through at least a limited range; spring means biasing themounting member to a, desired normal position relative to the supportingmember; clamping members movably mounted on the mounting member; andmeans for moving said last mentioned members toward each other to clampthe piece of work therebetween.

2. A driving device adapted to be attached to a rotating member having acenter point element and to clamp a piece of work in proper relation tosaid element, including: a supporting member adapted to be rigidlyattached to said rotating member; a mounting member mounted on saidsupporting member in such manner that circumferential movement isprevented but other movement with respect to the supporting member ispermitted both in a, plane transverse to the axis of the center pointelement and about an axis perpendicular to and intersecting the axis ofthe center point element; spring means biasing the mounting member to adesired normal position relative to the supporting member; clampingmembers movably mounted on the mounting member; and means for movingsaid last mentioned members toward each other to clamp the piece of worktherebetween.

3. A driving device adapted to be attached to a rotating member having acenter point element and to clamp a piece of work in proper relation tosaid element, including: a supporting member adapted to be rigidlyattached to said rotating member; a mounting member mounted on saidsupporting member in such manner that circumferential movement isprevented but other movement with respect to the supporting member ispermitted both in a plane transverse to the axis of the center pointelement and about an axis perpendicular to and intersecting the axis ofthe center point element; spring means comprising at least two springelements at each of at least two points on opposite sides of the axis ofthe center point element biasing the mounting member to a desired normalposition relative to the supporting member; clamping members movablymounted on the mounting member; and means for moving said last mentionedmembers toward each other to clamp the piece Of work therebetween.

4. A driving device adapted to be attached to a rotating member having acenter point element and to clamp a piece of work in proper relation tosaid element, including: a supporting member adapted to be rigidlyattached to said rotating member; a mounting member mounted on saidsupporting member, a driving connection element mounted between themounting member and supporting member in such manner that relativecircumferential movement is prevented but the driving connection elementmay twist about two axes perpendicular to each other and to the axis ofrotation of said rotating member; means connecting the mounting memberto the driving connection element for lateral movement therebetween;clamping members movably mounted on the mounting member; and means formoving said last mentioned members toward each other to clamp the pieceof work therebetween.

5. A driving device adapted to be attached to a rotating member having acenter point element and to clamp a piece of work in proper relation tosaid element, including: a supporting member adapted to be rigidlyattached to said rotating member; a mounting member, one of said membershaving a ball portion and the other having a cooperating socket portion;means providing a driving connection between the mounting member andsupporting member in such manner that circumferential movement isprevented but the ball portion may twist about two axes perpendicular toeach other and to the axisof rotation of said rotating member; meansconnecting the mounting member to the ball portion for lateral movementtherebetween; clamping members movably mounted on the mounting member;and means for moving said last mentioned members toward each other toclamp the piece of work therebetween.

6. A driving device adapted to be attached to a rotating member having acenter point element and to clamp a piece of work in proper relation tosaid element, including: a supporting member adapted to be rigidlyattached to said rotating member; a mounting member, one of said membershaving a ball portion and the other having a cooperating socket portionsuch that the mounting member is mounted on said supporting member foruniversal'movement with respect thereto, the remainder of the mountingmember being slidably movable with respect to its portion of the balland socket arrangement; means providing a driving connection between themounting member and supporting member in such manner thatcircumferential movement is prevented but other movement with respect tothe supporting member is permitted through at least a limited range;means connecting the mounting member to the ball portion for lateralmovement therebetween; clamping members movably mounted on the mountingmember; and means for moving said last mentioned members toward eachother to clamp the piece of work therebetween.;

7. A driving device adapted to be attached to a rotating member having acenter point element and to clamp a piece of work in proper relation tosaid element, including: a supporting member adapted to be rigidlyattached to said rotating member; a mounting member; a universal jointcomprising ball and socket parts, one of said parts being rigidlyconnected to one of said bers movably mounted on the mounting member;and means for moving said last mentioned members toward each other toclamp the piece of work therebetween.

8. A driving device adapted to be attached to a rotating member having acenter point element and to clamp a piece of work in proper relation tosaid element, including: supporting member adapted to be rigidlyattached to said rotating member; a mounting member; a universal jointcomprising ball and socket parts, one of said parts being rigidlyconnected to one of said members and the other of said parts beingconnected to the other member in such manner as to permit slidingmovement in a plane transverse to the axis of the center point element,this latter connection including means preventing relativecircumferential movement; means providing a driving connection betweenthe parts of the joint in such manner that relative circumferentialmovement is prevented but other movement between the parts is permitted;clamping members movably mounted on the mounting member; and means formoving said last mentioned members toward each other to clamp the pieceof the work therebetween.

9. A driving device adapted to be attached to a rotating member having acenter point element and to clamp a piece of work in proper relation tosaid element, including: a supporting member comprising two portionsmovable with respect to each other along the axis of the center pointelement, one of said portions being adapted to be rigidly attached tothe rotating member; a mounting member mounted on the other portion ofthe supporting member in such manner that circumferential movement isprevented but other movement with respect to the supporting member ispermitted through at least a limited range; spring means biasing themounting member to a desired normal position relative to the supportingmember; clamping members movably mounted on the mounting member; andmeans for moving said last mentioned members toward each other to clampthe piece of work therebetween.

10. A driving device adapted to be attached to a rotating member havinga center point element and to clamp a piece of work in proper relationto said element, including: a supporting member comprising two portionsmovable with respect to each other along the axis of the center pointelement, one of said portions being adapted to be rigidly attached tothe rotating member; a mounting member mounted on the other portion ofthe supporting member for universal movement with respect thereto; meansproviding a driving connection between the mounting member andsupporting member in such manner that circumferential movement isprevented but other movement with respect to the supporting member ispermitted through at least a limited range; clamping members movablymounted on the mounting member; and means for moving said last mentionedmembers toward each other to clamp the piece of work therebetween.

11. A driving device adapted to be attached 0 to a rotating memberhaving a center point element and to clamp a piece of work in properrelation to said element, including: a supporting member comprising twoportions movable with respect to each other along the axis of the centerpoint element, one of said portions being adapted to be rigidly attachedto the rotating member; a mounting member; a universal joint comprisingball and socket parts, one of said parts being rigidly connected to oneof said members and the other of said parts being connected to the othermember in such manner as to permit sliding movement in a planetransverse to the axis of the center point element, this latterconnection including means preventing circumferential movement; meansproviding a driving connection between the parts of the joint in suchmanner that circumferential movement is prevented but other movementbetween the parts is permitted; clamping members movably mounted on themounting member; and means for moving said last mentioned members towardeach other to clamp the piece of the Work therebetween.

12. Apparatus of the character claimed in claim '7, including screwmeans for locking the mounting member in a desired normal positionrelative to the supporting member.

13. A driving device adapted to be attached to a rotating member havinga center point element and to clamp a piece of work in proper relationto said element, including: a supporting member comprising two portionsrotatable with respect to each other to effect movement therebetweenalong the axis of the center point element, one of said portions beingadapted to be rigidly attached to the rotating member; a mounting membermounted on the other portion of the supporting member in such mannerthat circumferential movement is prevented but other movement withrespect to the supporting member is permitted through at least a limitedrange; clamping members movably mounted on the mounting member; andmeans for moving said last mentioned members toward each other to clampthe piece of work therebetween.

14. A driving device adapted to be attached to a rotating member havinga center point element and to clamp a piece of work in proper relationto said element, including: a supporting member comprising two portionsrotatable with respect to each other to effect movement there betweenalong the axis of the center point element, one of said portions beingadapted to be rigidly attached to the rotating member; a cylindricalhousing member rigidly attached to the other portion; a mounting membermounted on the other portion of the supporting member in such mannerthat circumferential movement is prevented but other movement withrespect to the supporting member is permitted through at least a limitedrange; clamping members movably mounted on the mounting member; andmeans for moving said last mentioned members toward each other to clampthe piece of work therebetween.

15, A driving device adapted to be attached to a rotating member havinga center point element and to clamp a piece of work in proper relationto said element, including: a supporting member adapted to be rigidlyattached to said rotating member; a transverse mounting member mountedon said supporting member in such manner that circumferential movementis prevented but other movement with respect to the supporting member ispermitted through at least a limited range, said transverse memberhaving arm portions extending from the sides thereof; spring means onthe supporting member and cooperating with said arm portions for biasingthe mounting member to a desired normal position relative to thesupporting member; clamping members movably mounted on the mountingmember; and means for moving said last mentioned members toward eachother to clamp the piece of work therebetween.

16. A driving device adapted to be attached to a rotating member havinga center point element and to clamp a piece of work in proper relationto said element, including: a supporting member adapted to be rigidlyattached to said rotating member; a transverse mounting member mountedon said supporting member in such manner that circumferential movementis prevented but other movement with respect to the supporting member ispermitted through at least a limited range, said transverse memberhaving arm portions extending from the sides thereof and terminating inball parts; spring means comprising three leaf spring elements c0-operating with each of said ball parts for biasing the mounting memberto a desired normal position relative to the supportin member; clampingmembers movably mounted on the mounting member; and means for: movingsaid last mentioned members toward each other to clamp the piece of worktherebetween.

17. A driving device adapted to be attached to a rotating member havinga center point element and to clamp a piece of work in proper relationto said element, including: a supporting member adapted to be rigidlyattached to said rotating member; a transverse mounting member mountedon said supporting member in such manner that circumferential movementis prevented but other movement with respect to the supporting member ispermitted through at least a limited range, the connection between oneend of the transverse member and the supporting member including a blockof resilient material; clamping members movably mounted on the mountingmember; and means for moving said last men tioned members toward eachother to clamp the piece of work therebetween.

18. A driving device adapted to be attached to a rotating member havinga center point element and to clamp a piece of work in proper relationto said element, including: a supporting member adapted to be rigidlyattached to said rotating member; a transverse mounting member mountedon said supporting member in such manner that circumferential movementis prevented but other movement with respect to the supporting member ispermitted through at least a limited range, the connection between oneend of the transverse member and the supporting member including a blockof resilient material, the connection between the other end of thetransverse member and the supporting member being so constructed as topermit axial movement 1 of such end but prevent circumferential movementthereof; clamping members movabiy mounted on the mounting member; andmeans for moving said last mentioned members toward each other to clampthe piece of work therebetween.

19. A driving device adapted to be attached LO a rotating member havinga center point element and to clamp a piece of work in proper relationto said element, including: a supporting member adapted to be rigidlyattached to said rotating member; a mounting member; a universal jointcomprising ball and socket parts, one of said parts being rigidlyconnected to one of said members and the other of said parts beingconnected to the other member in such manner that circumferentialmovement is prevented but sliding movement in a plane transverse to theaxis of the center point element is permitted; means providing a drivingconnection between the parts of the joint in such manner thatcircumferential movement is prevented but other movement between theparts is permitted; clamping members movabiy mounted on the mountingmember; means for moving said last mentioned members toward each otherto clamp the piece of work therebetween; and spring means biasing themounting member to a desired normal position relative to the supportingmember.

WILLIAM J. NIGH'I'INGALE.

